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MULTIPLE CHOICE. Choose the one alternative that best completes the statement or answers the question. 1) A physical change A) occurs when propane is burned for heat. B) occurs when iron rusts. C) occurs when glucose is converted into energy within your cells. D) occurs when water is evaporated. E) occurs when sugar is heated into caramel 23 2) A chemical change A) occurs when methane gas is burned. B) occurs when salt is dissolved in water, C) occurs when paper is shredded. D) occurs when powdered lemonade is stirred into water. E) occurs when water is vaporized. 3) 3) How many grams of Li3N can be formed from 1.75 moles of Li? Assume an excess of nitrogen. 6 Li(s)+N2(g) - 2 Li3N(s) A) 61.0 g LigN B) 20.3 g LizN C) 58.3 g LigN D) 18.3 g LigN E) 15.1 g LizN 4) A 12.39 g sample of phosphorus reacts with 42.54 g of chlorine to form only phosphorus trichloride (PC13). If it is the only product, what mass of PClz is formed? A) 79.718 B) 91.868 C) 30.15 g D) 140.018 E) 54.93 g TRUE FALSE. Write T' if the statement is true and F if the statement is false. 5) Given the recipe: 2 cups flour +1 egg +3 oz blueberries -- 4 muffins. You can make 1 dozen muffins from 3 eggs. 5) 6) Stoichiometry is a chemist's version of following a recipe. 6) MULTIPLE CHOICE. Choose the one alternative that best completes the statement or answers the question. 7) According to the following balanced reaction, how many moles of NO are formed from 8.44 7 ) moles of NO2 if there is plenty of water present? 3 NO2(g)+H2O(1) -- 2 HNO3(aq) + NO(g) A) 25.32 moles NO B) 8.44 moles NO C) 5.63 moles NO D) 2.82 moles NO E) 12.66 moles NO

Answer 1

I D occurs when water is evaporated since only phase changed but chenical composition is same 2. A) Methane is burned: Chemical properties changes, new conpounds are fornied